Which type of window typically features one movable sash that slides horizontally and one fixed sash?

The type of window that typically features one movable sash that slides horizontally and one fixed sash is indeed the sliding window. Sliding windows are designed to operate by one panel or sash gliding over another fixed panel, which allows for easy opening and closing without requiring any additional space for the window to swing open. This design is especially beneficial in areas where space is limited, providing functionality while maintaining unobstructed views.

In contrast, double hung windows consist of two movable sashes that slide vertically, allowing for flexibility in ventilation and light. A picture window is fixed and does not open, often used to maximize views without the distraction of a moving part. A casement window hinges on one side and swings outward, which is a very different operating mechanism. Thus, the unique characteristics of the sliding window confirm why it is the correct answer in this context.